Scoping studies for small steady state tokamak for divertor testing

Abstract

Initial global scoping studies have been done for small, steady-state, copper coil, beam-driven tokamaks that are dedicated to divertor testing. The usual ITER (International Thermonuclear Experimental Reactor) global physics models (beta limit, energy confinement, and analytic divertor heat load calculation) are incorporated, and for performance criteria it is required that the divertor heat load and plasma collisionality in the edge region be similar to those expected in ITER. The smallest, lowest-cost devices satisfying these constraints tend to have major radius below 1 m, plasma current of 0.5 to 1 MA, low aspect ratio, and costs of a few tens of millions of dollars. Injection powers of about 4 to 5 MW are needed to sustain the plasma current, maintain plasma power balance, and provide the required divertor heat load.